The invention relates in general to cooling fans used in electronic devices and in particular to cooling fans which are controlled in part based on the audio output level of the electronic device and/or the ambient noise level.
The power dissipated during operational use of an electronic circuit reveals itself as heat. The heat generated by an integrated circuit typically increases with increasing transistor density and with increasing clock frequency. The eventual temperature of a semiconductor substrate in a stationary state is determined by the balance between the heat generated and the heat carried off of the substrate. A conventional way to handle excessive heat is providing forced cooling using a fan.
The problem with using a fan is that a fan is typically turned on and left on during operation of the electronic device causing fan noise to interfere with the playing of music or other audio or the general quiet of an environment in which the device is used. Certain circuits requiring cooling however, tend to operate in bursts. That is, the circuit may alternatively remain idle for a period of time and then operate at its maximum or near maximum capacity for another period of time. In fact depending on the audio output of the computer, the fan noise can be quite annoying, such as when trying to listen to a CD. At other times during computationally intensive activities, such as a computer game that can be quite loud, the fan is hardly detectable in the background noise.
Accordingly, it is an object of the invention to provide a cooling fan control mechanism that is responsive to heat generated within the electronic device and/or semiconductor substrate as well as being responsive to the audio output of the electronic device.
It is another object of the invention to control the cooling fan based on the heat generated within the electronic device and/or semiconductor and the ambient noise.